In today's business climate, industry fortunes rise and fall on whether information is exchanged in an efficient manner. Cell phones, pagers, and the Internet have thrived because each technology allows businesses to exchange critical market information at a moment's notice. In addition, such technologies allow individuals to keep abreast of recent developments with family and friends. In short, many segments of our modern society require instant access to accurate, up-to-the-minute information.
Digital subscriber line (DSL) technology is one technology that provides users with high-speed data. As networking technology has matured, data rates have increased from 20 kilobits per second (kb/s) in 1975, to 100 Mb/s with modern VDSL. In other words, DSL customers in today's “information age” can receive data approximately 5,000 times as fast as network customers of thirty years ago. To bring customers into this modern “information age”, DSL developers have spent billions of dollars to develop the technology as we now know it. To continue to increase data rates at such a remarkable pace, DSL developers will likely be required to spend significant capital resources for many years to come. Thus, DSL technology showcases the premium that our society places on fast and accurate information.
A DSL communication system includes two modems which communicate over an ordinary telephone line (i.e., a twisted pair of copper wires in a conventional residential telephone system). One specific area in which DSL technology is progressing is by trying to limit the number of errors as data is transmitted over the telephone line.
One method of limiting such errors is to selectively reduce the data rate and/or the power of their transmitted signals when communicating modems are not using the full data rate supplied to them. For example, one customer may have a DSL connection that constantly supports bandwidth for simultaneous supply of data to three television sets, even though the customer typically uses only one set at a given time. In early DSL systems, the customer would always receive bandwidth to drive all three television sets simultaneously, even if only one was in use. This would result in “extra” bandwidth being transmitting to the customer, which could lead to undesirable and unjustified cross-talk on the line. Current DSL methods, however, can request a bandwidth that corresponds to the data rate they require. In the illustrative example, the customer's modem would know whether one, two, or three televisions were on, and would request the appropriate data rate to be provided over the DSL line. By employing such methods, modern DSL systems can limit the excess data on the line, thereby reducing the cross-talk on the line while still providing the data rate the customer requires. In other case, the bandwidth of the DSL system can be reduced in the respond on the degradation in the noise environment. When noise conditions are improved back, the DSL system will return to supple high data rate again.
While the existing methods for adjusting data rates are sufficient for their stated purpose, the methods are not sufficient to accurately account for changes in communication parameters during communication service without degrading or interrupting the communication service. Thus, improved methods and systems are needed.